Adeney — Dissolved Gases and Fermentative Changes. 593 



PART II. 



Experiments with difi&cultly Fermentable Matters. 



Colouring Matters of Peat. 



As an example of difficultly fermentable organic matters, I have employed an 

 extract of fresh peat, collected from a bog which was slightly submerged under 

 running water, and which was situated on one of the Wicklow mountains, and 

 far removed from any soui'ce of contamination with animal matters. 



The sample of peat was collected on September 15th, 1893. 



Two days after, an extract was prepared from it by boiling it in tap-water con- 

 taining a little sodium hydrate. The extract was filtered into a large glass stop- 

 pered jar, which it filled to about two-thirds of its capacity. The extract was then 

 of a deep brown, and it was allowed to ferment until March 8th in the 

 following year, the stopper of the jar being taken off from time to time to 

 renew the air. It was then thoroughly mixed with about five times its bulk of 

 tap-water, and allowed to settle till the following day, when about six litres were 

 decanted off, and the different experiments commenced, which are recorded in 

 Tables XIV and XV. 



The results of these experiments were looked forward to with very much 

 interest for several reasons — 



First, it was known that peaty-colouring matters in river-waters suffered but 

 little oxidation or other change, unless the waters were subjected to the action of 

 such bodies as clay, when the peaty matters were more or less completely separated 

 by the precipitating action of the clay. There was good reason to believe, how- 

 ever, that the peaty matters in water, when fresh, do undergo at least a slight 

 chemical change. This was evident from the analyses published in the " Sixth 

 Report of the Rivers Pollution Commissioners."* 



These show that the proportion of carbon to nitrogen in unoxidized peaty 

 matter contained in upland surface water is as 11 "9 : 1 ; but in peaty matter which 

 has been exposed to oxidation in lakes or large reservoirs, the proportion became 

 5-9:1. 



It was quite an open question, however, whether these matters undergo fer- 

 mentation when present alone, or whether they exert any influence on the fermen- 

 tation of fermentable matters when present together with such in a water. 



* See also Dr. P. Frankland's Article on "Water in " Thorpe's Dictionary of Applied Chemistry," 

 vol. iii., p. 965. 



